This study focuses on two physical processes for waves in shallow waters off the Mackenzie Delta: bottom friction and depth-induced breaking terms. We use field observations of winds and waves, the state-of-the-art Simulating Waves Nearshore (SWAN) model, and reanalysis wind and wave data. The two field observation periods are an August 2008 field experiment, during which in situ field data were collected, and an Arctic storm when data were recorded by buoy measurements from 4 to 6 August 1991. Wind and wave development processes are analyzed during these two periods with comparisons to observed winds and waves. Our analyses show that bottom friction is the main shallow water physical process during the August 2008 field experiment, whereas depth-induced breaking is the dominant shallow water physical process during the 4-6 August 1991 storm, in conjunction with the effects of bottom friction. The SWAN wave model is used to investigate the shallow water physical processes during these two observation periods. Simulation results indicate that the model can give reasonable results, with an appropriate Collins coefficient of 0.006 and a wave breaking parameter of 0.55 to represent bottom friction and depth-induced breaking physics, respectively.
We present work on the development of a long range standoff concealed weapons detection system capable of imaging under very heavy clothing at distances exceeding 100 m with a cm resolution. The system is based off a combination of phased array technologies used in radio astronomy and SAR radar by using a coherent, multi-frequency reconstruction algorithm which can run at up to 1000 Hz frame rates and high SNR with a multi-tone transceiver. We show the flexible design space of our system as well as algorithm development, predicted system performance and impairments, and simulated reconstructed images. The system can be used for a variety of purposes including portal applications, crowd scanning and tactical situations. Additional uses include seeing through dust and fog.
Field data, remote sensing, and Inuvialuit knowledge were synthesized to document regional ecological change in the outer Mackenzie Delta and to explore the timing, causes, and implications of this phenomenon. In September 1999, a large magnitude storm surge inundated low-lying areas of the outer Mackenzie Delta. The storm was among the most intense on record and resulted in the highest water levels ever measured at the delta front. Synthesis of scientific and Inuvialuit knowledge indicates that flooding during the 1999 storm surge increased soil salinity and caused widespread vegetation death. Vegetation cover was significantly reduced in areas affected by the surge and was inversely related to soil salinity. Change detection analysis, using remotely sensed imagery bracketing the 1999 storm event, indicates severe impacts on at least 13 200 ha of terrestrial vegetation in the outer delta. Inuvialuit knowledge identifying the 1999 surge as anomalous is corroborated by geochemical profiles of permafrost and by a recently published paleo-environmental study, which indicates that storm surge impacts of this magnitude have not previously occurred during the last millennium. Almost a decade after the 1999 storm surge event, ecological recovery has been minimal. This broad-scale vegetation change is likely to have significant implications for wildlife and must be considered in regional ecosystem planning and in the assessment and monitoring of the cumulative impacts of development. Our investigations show that Inuvialuit were aware of the 1999 storm surge and the environmental impacts several years before the scientific and regulatory communities recognized their significance. This study highlights the need for multidisciplinary and locally informed approaches to identifying and understanding Arctic environmental change.
The oceanographic conditions of the Mackenzie River plume in the Arctic Ocean were examined during a 12-day period in August 2007. Field observations in the river channel and the delta region (2-6 m depth), ship-based observations on the shelf and satellite observations of sea surface temperatures indicate that movements of plume density fronts cause changes in water temperatures of over 10 C over a few days. We used a 1D model to compare the strength of stratification versus surface wind stress, and a 3D numerical model to simulate the plume motions under forcing from the river flows, local wind and water level variations from tides and wind-driven surge. The results indicate that the coastal region is stratified with a similar to 2 m thick surface plume even in water depths of 3-4 m, resulting in strong vertical variation of horizontal currents. Moderate easterly winds of 5-10 m/s are sufficient to induce offshore transport of the surface plume and onshore transport of the deeper shelf water, leading to large fluctuations in temperature and salinity in the coastal region. This study examined a period of offshore transport and mean water level set-down, and indicates the rapid response of the plume to wind over the shallow delta. (c) 2010 Elsevier Ltd. All rights reserved.
Cultural awareness training is seen as a necessity in the military, in international business, and in diplomacy. The Culturally-Affected Behavior project has defined a framework for encoding cultural norms and values that facilitates the creation of human behavior models having cultural knowledge separate from domain knowledge. We evaluated a simulation based on the framework as a tool for learning cultural norms. Users were provided a worked example of a meeting with a first virtual character as a training session, and were subsequently able to distinguish appropriate socio-cultural actions from inappropriate actions in a meeting with a second character of the same culture, and in a judgment survey.
Abstract : Increasingly, the military has requirements for teaching cultural awareness, which demands flexible representations of cultural knowledge. The Culturally-Affected Behavior project seeks to define a language for encoding ethnographic data in order to capture cultural knowledge and use that knowledge to affect human behavior models. Having anthropologists encode ethnographic data will validate the language and will result in a library of culture models for immersive training.
Culture and emotions have a profound impact on human behavior. Consequently, high-fidelity simulated interactive environments (e.g., trainers and computer games) that involve virtual humans must model socio-cultural and emotional effects on agent behavior. In this paper we discuss two recently fielded systems that do so independently: Culturally Affected Behavior (CAB) and EMotion and Adaptation (EMA). We then propose a simple language that combines the two systems in a natural way thereby enabling simultaneous simulation of culturally and emotionally affected behavior. The proposed language is based on matrix algebra and can be easily implemented on single- or multi-core hardware with an off-the-shelf matrix package (e.g., MATLAB or a C++ library). We then show how to extend the combined culture and emotion model with an explicit representation of religion and personality profiles.
SBIR has completed design and development of prototype emitter arrays and is completing custom cryogenic vacuum device packaging and support electronics for the Optimized Arrays for Space-background Infrared Simulation (OASIS) program. The OASIS array is a 512 x 512 device featuring high output dynamic range, a selectable analog/digital scene data interface, and the capability to operate from cryogenic to ambient substrate temperatures - thereby providing an enabling technology for projection of simulated radiance of space-background scenes. Prototype emitter production has been completed at RTI International in support of initial deliveries. The OASIS array package incorporates novel electrical bussing schemes optimized for the OASIS RIIC and a modular architecture to allow user re-configuration of both window and emitter shield. The OASIS package leverages LFRA operation features, and supports both ambient and cryogenic chamber-based operation with a minimum of mechanical and electrical re-configuration. The OASIS close support electronics (CSE) supports both analog and digital input data modes, while providing easy electronic connection between arrays installed in the cryogenic chamber and the external control and scene-generation systems. We present a technical overview of the OASIS array/package and CSE designs, and will report on measured radiometric performance from prototype OASIS arrays.
The results of testing two technologies based on gas microplasmas for the generation of UV-visible light is detailed. A microcavity device from the University of Illinois at Champaign-Urbana have been delivered with an Ar/D2 gas mixture. Emission from the Ar/Ne as well as an Ar/D2 eximer in the 250-400nm range, as well as argon lines in the visible and near infrared, are measured. Development of addressing arrays is discussed as is the potential of emission in other wavebands with other gas species. A 100x40 array of plasmaspheres combined with electronics capable of projecting images at 1000 Hz with 10 bits of grayscale resolution has been built and tested. This system, built by Imaging Systems Technology (IST), is capable of accepting DVI output from a HWIL system and projecting UV from a gas captured in the spheres. This array uses an argon neon gas mixture to produce UV, visible and near infrared light. Performance data discussed for both arrays include: maximum and minimum brightness, uniformity, spectral content, speed, linearity, crosstalk, resolution, and frame rate. Extensions of these technologies to larger arrays with wider spectral bandwidth for use in multispectral projectors are discussed.
There is an incredible amount of system engineering involved in turning the typical infrared system needs of probability of detection, probability of identification, and probability of false alarm into focal plane array (FPA) requirements of noise equivalent irradiance (NEI), modulation transfer function (MTF), fixed pattern noise (FPN), and defective pixels. Unfortunately, there are no analytic solutions to this problem so many approximations and plenty of "seat of the pants" engineering is employed. This leads to conservative specifications, which needlessly drive up system costs by increasing system engineering costs, reducing FPA yields, increasing test costs, increasing rework and the never ending renegotiation of requirements in an effort to rein in costs. These issues do not include the added complexity to the FPA factory manager of trying to meet varied, and changing, requirements for similar products because different customers have made different approximations and flown down different specifications.Scene generation technology may well be mature and cost effective enough to generate considerable overall savings for FPA based systems. We will compare the costs and capabilities of various existing scene generation systems and estimate the potential savings if implemented at several locations in the IR system fabrication cycle. The costs of implementing this new testing methodology will be compared to the probable savings in systems engineering, test, rework, yield improvement and others. The diverse requirements and techniques required for testing missile warning systems, missile seekers, and FLIRs will be defined. Last, we will discuss both the hardware and software requirements necessary to meet the new test paradigm and discuss additional cost improvements related to the incorporation of these technologies.
The leading IR scene projection (IRSP) device technology, resistive emitter arrays, has grown from its early roots in the uncooled microbolometer community into a separate and highly specialized field of its own. IRSP systems incorporating "microbolometers running backwards" are critical tools now ubiquitous in laboratory testing and evaluation of high performance IR sensors and their embedded algorithms. Adoption of IRSPs has reduced the scope of flight/field testing, producing dramatic resource savings and strong system development advantages.Modern IRSP systems provide the capability to project high-resolution (1024 x 1024), high-temperature (750 K) dynamic MWIR-LWIR imagery at frame rates up to 200 Hz, with 16-bit input resolution. Novel IRSP systems are now being developed to test advanced FPAs and sensors requiring wide-format (768 x 1536), cryogenic background (50-80 K), fast-framing (400 Hz), and/or very high-temperature (2500 K) dynamic IR simulation in order to be properly evaluated.The ongoing cycle of sensor improvement and test system evolution is perfectly illustrated by the parallel development of IRSP and emerging FPA/sensor technologies. The cross-pollination of technology between the sensor and projector domains continues to bring innovation to both communities. Technological trends related to semiconductor and microelectrical-mechanical system (MEMS) device fabrication, real-time digital video processing, and EO system design are being exploited by both sensor and projector developers alike - with advantages realized by both.This paper presents a lighthearted overview of the technical evolution of IRSP from its early microbolometer roots, discusses current and emerging IRSP capabilities, illustrates the device-level to system-level synergy between sensors and projectors, and offers a peek into the advanced EO simulation capabilities and technologies which will be required to address emerging FPA and sensor trends.
SBIR has completed development of the Large Format Resistive Array (LFRA) Infrared Scene Projector (IRSP) and shipped the first production system. Nine more systems are in production and will be shipped to several US Government customers on approximately six week centers. The commercial name of the LFRA IRSP is Mirage XL. System performance meets a broad range of program requirements and SBIR has been extremely successful in producing this ground breaking projector. Tests performed on System #1 reveal broad compliance to the specification and, in particular, outstanding emitter array performance. Key emitter requirements that have been met or exceeded include Operability, Maximum Apparent Temperature, and Array Uniformity. Key System specifications are: Large-format emitter array (1024x1024); High maximum apparent temperature (>700K); 200 Hz full-frame operation; 400 Hz static window mode (1024x512); Non Uniformity (uncorrected) <10%.